全文获取类型
收费全文 | 1586篇 |
免费 | 19篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 47篇 |
化学工业 | 253篇 |
金属工艺 | 45篇 |
机械仪表 | 39篇 |
建筑科学 | 21篇 |
能源动力 | 56篇 |
轻工业 | 74篇 |
水利工程 | 9篇 |
无线电 | 198篇 |
一般工业技术 | 324篇 |
冶金工业 | 417篇 |
原子能技术 | 39篇 |
自动化技术 | 86篇 |
出版年
2023年 | 4篇 |
2022年 | 18篇 |
2021年 | 18篇 |
2020年 | 10篇 |
2019年 | 11篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 21篇 |
2015年 | 13篇 |
2014年 | 32篇 |
2013年 | 70篇 |
2012年 | 34篇 |
2011年 | 77篇 |
2010年 | 57篇 |
2009年 | 65篇 |
2008年 | 63篇 |
2007年 | 46篇 |
2006年 | 47篇 |
2005年 | 46篇 |
2004年 | 32篇 |
2003年 | 38篇 |
2002年 | 37篇 |
2001年 | 35篇 |
2000年 | 40篇 |
1999年 | 39篇 |
1998年 | 174篇 |
1997年 | 102篇 |
1996年 | 59篇 |
1995年 | 44篇 |
1994年 | 40篇 |
1993年 | 34篇 |
1992年 | 19篇 |
1991年 | 23篇 |
1990年 | 20篇 |
1989年 | 24篇 |
1988年 | 20篇 |
1987年 | 12篇 |
1986年 | 21篇 |
1985年 | 23篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 14篇 |
1981年 | 13篇 |
1980年 | 15篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 32篇 |
1975年 | 5篇 |
1974年 | 4篇 |
排序方式: 共有1608条查询结果,搜索用时 0 毫秒
41.
Nishioka T. Soujaeff A. Hasegawa T. Tsurumaru T. Abe J. Takeuchi S. 《Photonics Technology Letters, IEEE》2008,20(5):354-356
We have conducted a single-photon interference experiment over an 80-km optical fiber using a pulse-driven heralded single-photon source (HSPS). To the best of our knowledge, this is, thus far, the longest distance over which a single-photon interference experiment has been conducted using HSPSs (continuous-wave-pumped or pulse-driven). The effect of the 80-km transmission on the dispersion and fluctuation of polarization are more severe than those in our previous 40-km quantum key distribution (QKD) experiment. We have overcome the difficulties by some fine tunings and low-jitter controlling. By conducting ten consecutive transmission experiments over a total time of 30 min, an average quantum bit-error rate (QBER) of 7.9 plusmn 1.2% has been obtained. This QBER is lower than the threshold QBER of 10.55% which is considered as a limit for unconditional security for the QKD under negligible multiphoton emission. 相似文献
42.
Yuichi Terazawa Masashi Mikami Takashi Itoh Tsunehiro Takeuchi 《Journal of Electronic Materials》2012,41(6):1348-1353
By using first-principles cluster calculations, we identified that Ta or W substitution for V is useful for decreasing the lattice thermal conductivity of the Fe2VAl Heusler alloy without greatly affecting the electron transport properties. It was clearly confirmed that the Fe2(V1?x Ta x )Al0.95Si0.05 (x?=?0, 0.025, 0.05), Fe2(V0.9?x Ta x Ti0.1)Al (x?=?0, 0.10, 0.20), and Fe2(V0.9?2x W x Ti0.1+x )Al (x?=?0, 0.05, 0.10) alloys indeed possessed large Seebeck coefficient regardless of the amounts of substituted elements, while their lattice thermal conductivity was effectively reduced. As a result of partial substitution of Ta for V, we succeeded in increasing the magnitude of the dimensionless figure of merit of the Heusler phase up to 0.2, which is five times as large as the Ta-free compound. 相似文献
43.
44.
A GaAs/AlGaAs directional coupler switch, for the first time with a device length shorter than 1 mm, has been fabricated by utilising the good controllability of molecular beam epitaxy and reactive ion beam etching. The switching voltage is as low as 5V. The extinction ratio is 17dB for a crossover state and 14dB for a straight-through state. 相似文献
45.
46.
A novel sealing material based on a CNT-rubber composite was developed for use in producing oil from deep, hot reservoirs. Fully dispersed and better bondings are two critical advances that enhance its mechanical properties. Authors solved the critical issues and clarified the mechanism of nano network reinforcement using test data. The resulting sealing solution underwent field tests around the world, and it marks a rare success story for the use of nanotechnology in the oilfield. 相似文献
47.
Takuya Isomura Akimasa Takeuchi Kenta Shimba Kiyoshi Kotani Yasuhiko Jimbo 《Electrical Engineering in Japan》2014,187(4):42-50
Recently, there has been abundant research using multineuron recording, but there are many problems with extracting the features from the obtained spike time series, which are huge in volume and complex. Here we introduce a new method of estimating synaptic connection strengths between neurons by fitting to the Izhikevich model by maximum likelihood estimation. We demonstrate that our method can estimate connection strengths from spike time series given by a simulated neural ensemble and can estimate nonconnectivity between two independent cultured neuronal networks. These results suggest that our method is applicable to network and plasticity analysis of neuronal networks. 相似文献
48.
Shinji Miwa Norio Yamamoto Katsuhiro Hayashi Akihiko Takeuchi Kentaro Igarashi Hiroyuki Tsuchiya 《International journal of molecular sciences》2022,23(3)
Simple SummaryChondrosarcomas develop chemoresistance to standard anticancer drugs, making it difficult to control unresectable or metastatic chondrosarcomas. To improve the clinical outcomes of chondrosarcoma, new treatment approaches, such as molecule-targeting agents and immunotherapy, are needed. Recent research has revealed promising biomarkers and therapeutic targets for chondrosarcoma. In addition, several molecule-targeting agents have shown favorable antitumor activities in several clinical studies in patients with advanced sarcomas, including chondrosarcoma. This review summarizes recent basic studies on biomarkers and therapeutic targets and recent clinical studies on treating chondrosarcomas.AbstractDue to resistance to standard anticancer agents, it is difficult to control the disease progression in patients with metastatic or unresectable chondrosarcoma. Novel therapeutic approaches, such as molecule-targeting drugs and immunotherapy, are required to improve clinical outcomes in patients with advanced chondrosarcoma. Recent studies have suggested several promising biomarkers and therapeutic targets for chondrosarcoma, including IDH1/2 and COL2A1. Several molecule-targeting agents and immunotherapies have shown favorable antitumor activity in clinical studies in patients with advanced chondrosarcomas. This review summarizes recent basic studies on biomarkers and molecular targets and recent clinical studies on the treatment of chondrosarcomas. 相似文献
49.
Masayoshi Sugawara Tetsuya Suzuki Atsushi Totsuka Masayasu Takeuchi Kunimasa Ueki 《Starch - St?rke》1994,46(9):335-337
The corn hull dietary fiber was decomposed into their components such as cellulose, hemicellulose-A, -B, -C, -other and lignin by the Siegel method, and their contents were 16%, 1%, 57%, 14% and 2%, respectivity. The components of ordinary corn fiber were insoluble in water, but several decomposed fractions were able to dissolved. The solubility in water of hemicellulose-B was well and of hemicellulose A was slightly, but other fractions were insoluble. Hemicellulose-A, -B, -C and -other fractions were made up of about 30% of arabinose and 50% of xylose. Uronic acid contents and solubility in water of each hemicellulose fraction were mutually related. 相似文献
50.
Feng Ren Shingo Ishida Nobuyuki Takeuchi 《Journal of the American Ceramic Society》1993,76(7):1825-1831
The distribution and chemical states of vanadium in V-doped ZrO2 were studied to clarify the origin of the color of vanadium-zirconium yellow pigment in comparison with vanadium-tin yellow pigment. ESCA data and measurements of lattice constants of V-doped ZrO2 revealed that vanadium was dissolved mainly as V4+ substituting for Zr in ZrO2 lattice, and its solubility limit was 0.5 wt% as V2 O5 . It was found that the yellow color of vanadium-zirconium yellow was produced predominantly by the dissolved vanadium and that the contribution of vanadium oxide on ZrO2 grains to the yellow color was about 1/30 of that of the dissolved vanadium when compared on the basis of equimolar quantity of vanadium. Most of the undissolved vanadium oxide was in an amorphous or a poorly crystallized state. 相似文献